Using batteries, such as lithium batteries, is known in electronic devices such as mobile phones, hand-held devices, notebooks, etc. Lithium batteries should be conveniently managed to avoid malfunctioning and damage that may also lead to battery explosion. For these reasons, batteries are equipped with integrated circuits that measure charge, voltage, temperature, and protect the battery from being damaged.
The batteries used for electronic devices typically comprise a plurality of cells connected in series and one or two integrated circuits that perform measuring and protecting operations. In general, when two integrated circuits are used, one is responsible for measurement operations and the other operates to send out communications that contain indications on the battery capacity or on malfunctioning, and is capable of making decisions concerning battery malfunctioning or other information.
Integrated circuits currently existing in the market are only for batteries with a defined number of cells, e.g. 12 or multiples of 12. If a battery with 8 cells is used, integrated circuits set up for a battery with 12 cells are required; thereby, the final device or “battery pack” is not optimized in terms of cost/performance ratio.
Another integrated circuit in battery packs currently being used is configured to protect the battery cells if the voltage of the cells exceeds or decreases below certain levels.
Firmware implemented in the integrated circuits of the battery packs comprises the functions of determining the beginning of the charge, activating the function of cell balancing, and estimating the lifetime of the battery pack. Such firmware is stored inside the integrated circuits and may not be modified as it is not accessible to the user. Therefore, particular battery management algorithms may not be inserted into the integrated circuits, such as for example, management algorithms related to the high safety of the battery or for the balancing function of the cells known as “cell balancing”. Cell balancing is of interest due to the cells not all having the same, but having different, capacities due to manufacturing tolerances. To allow all the cells of a battery to be charged to the same level, a greater amount (or percentage) of current is required to be directed towards some cells and a smaller amount towards others; this requires a higher charge time.
Document “SBS 1.1-Compliant gas gauge and protection enabled with impedance track” SLUS757B-JULY 2007-REVISED APRIL 2008, Texas Instruments, describes a single integrated circuit adapted to operate the monitoring and protecting functions for batteries of Lithium-ion (Li-ion) or Lithium-polymer (Li-polymer) type, for example.
In view of the state of the art, it is desired to provide a modular device for protecting and monitoring a battery that is different from those known in the art.